印度喜马偕尔邦的按蚊复合种的流行情况。

Prevalence of sibling-species of Anopheles complex in Himachal Pradesh, India.

机构信息

Environmental Epidemiology Division, ICMR-National Institute of Malaria Research, New Delhi, India.

Kangra Study Site, ICMR-National Institute of Malaria Research, New Delhi, India.

出版信息

J Vector Borne Dis. 2021 Jan-Mar;58(1):85-89. doi: 10.4103/0972-9062.321745.

DOI:10.4103/0972-9062.321745

PMID:34818868

Abstract

BACKGROUND & OBJECTIVES: Malaria is one of the most infectious and life-threatening vector borne disease in the tropics. Climate change can significantly influence malaria epidemiology and expansion of malaria vectors to hilly regions of Himachal Pradesh in India, hitherto considered areas of low transmission. Entomological surveillance in Kangra district of Himachal Pradesh revealed high density of a proven efficient vector of malaria, Anopheles fluviatilis, but transmission intensity of malaria was found very low. It was therefore considered prudent to investigate the sibling-species composition of An. fluviatilis complex in Kangra valley to ascertain their role in transmission of malaria.

METHODS

The study was undertaken in six villages in Kangra district of Himachal Pradesh, India. A total of 4446 mosquitoes were collected during the one-year study period (2018) and processed in pools of ten for molecular characterization. DNA extraction and multiplex PCR was performed on 900 An. fluviatilis mosquitoes for differentiation of sibling-species. ELISA was used to detect Plasmodium falciparum and Plasmodium vivax circumsporozoite proteins in 3790 An. fluviatilis samples.

RESULTS

Among prevalent mosquito species, An. fluviatilis was the predominant species constituting 69.5% of total mosquito collection. Sibling-species U was found in 92.22% and species T in 7.78% samples assayed. ELISA confirmed the absence of evidence of malaria parasite in any of the An. fluviatilis mosquitoes screened. Based on the difference in the sequences of conserved regions of the 28SrDNA, sibling-species U was confirmed as prevalent in the study villages.

INTERPRETATION & CONCLUSION: Study revealed that in Kangra district, An. fluviatilis sibling-species U is predominant followed by species T, and both are non-vectors. The absence of malaria parasite and zoophagic nature of An. fluviatilis established through blood meal analysis, confirmed that both U and T are non-vector sibling-species.

摘要

背景与目的

疟疾是热带地区最具传染性和威胁生命的虫媒病之一。气候变化会显著影响疟疾的流行病学和疟疾传播媒介向印度喜马偕尔邦丘陵地区的扩展，迄今这些地区被认为是低传播区。在喜马偕尔邦的康格拉区进行的昆虫学监测显示，一种已被证实为高效疟疾传播媒介的疟蚊——淡色库蚊——的密度很高，但疟疾的传播强度却非常低。因此，有必要调查康格拉谷淡色库蚊复合体的种系组成，以确定它们在疟疾传播中的作用。

方法

本研究在印度喜马偕尔邦康格拉区的 6 个村庄进行。在为期一年的研究期间（2018 年）共收集了 4446 只蚊子，并以 10 只为一组进行处理，进行分子特征分析。对 900 只淡色库蚊进行 DNA 提取和多重 PCR，以区分种系。对 3790 只淡色库蚊样本进行酶联免疫吸附试验（ELISA），以检测恶性疟原虫和间日疟原虫环子孢子蛋白。